Year	Percent
1991	46.233
1992	46.285
1993	46.372
1994	46.417
1995	46.493
1996	46.744
1997	47.448
1998	47.748
1999	48.006
2000	48.187
2001	48.601
2002	49
2003	49.365
2004	49.859
2005	50.413
2006	50.603
2007	50.889
2008	51.306
2009	51.737
2010	52.078
2011	52.053
2012	52.169
2013	52.328
2014	52.53
2015	52.77
2016	52.063
2017	51.626
2018	51.335
2019	51.206
2020	51.267
2021	51.091
2022	51.001